[en] Performing muscular exercise regularly is generally recommended to diabetics; indeed, exercise increases muscle insulin sensitivity, helps fighting overweight and, at least partly, tends to correct plasma lipids abnormalities, thus contributing to limit the development of atherosclerosis. Moreover, the practice of sport is beneficial from a psychological point of view, because, thanks to it, diabetic patients can match, even surpass, "the others" and overcome what they often consider as a disability. However, diabetes--especially type 1, insulin dependent, diabetes--deeply modifies the metabolic adaptations to muscular exercise; consequently, exercise must be performed only in good metabolic control conditions, for avoiding a worsening of ketonaemia. In adequately controlled diabetics, muscular exercise can be beneficial by reducing blood glucose levels; it can also lead to hypoglycaemia occurring during or after the exercise bout. In order to reduce the risk of exercise-induced hypoglycaemia, diabetics have to know how to modify three essential parameters of their treatment: (1) increase carbohydrate intake before, during or after exercise; (2) reduce the dose of the insulin acting during exercise, and this in relation to the usual doses and to exercise intensity; (3) under some circumstances, modify the site of insulin injection according to the type of exercise performed. Taking into account these parameters, some general rules can be assessed, which are to be adapted to every particular situation; the use of home blood glucose monitoring before and after exercise is not only useful but sometimes mandatory.(ABSTRACT TRUNCATED AT 250 WORDS)